The Hartford Courant discovered what appears to have been an early username of Sandy Hook shooter Adam Lanza.
The article about Lanza's possible history as a Wikipedia editor includes comments, that when googled, match up with Wikipedia user Kaynbred.
A revision involving the Sept. 13, 2006, shooting at Dawson College in Montreal, in which one student was killed and 19 others wounded, is quite particular about how the article posted on Wikipedia describes the firearm used by the killer.
" '9mm' was listed as '.9mm.' People say that 9mm is anemic, but this is ridiculous," the poster believed to be Lanza says in explaining his revision.